Data Analysis
    Retatrutide

    Retatrutide Dropout Rates: How Many Quit and Why

    Between 6-16% of Phase 2 participants discontinued due to side effects. Here is what that tells us about retatrutide's real-world tolerability.

    Last updated: April 3, 202610 min read

    Retatrutide dropout rates from the Phase 2 clinical trial (Jastreboff et al., NEJM 2023) tell an important story about the drug's tolerability. While the headline weight loss of 24.2% is extraordinary, a medication only works if patients can stick with it. Discontinuation rates of 6-16% across dose groups — while slightly higher than semaglutide or tirzepatide — still mean that the vast majority of participants (84-94%) completed treatment. Understanding who quit and why helps set realistic expectations.

    Phase 2 Data

    Dropout data is from the Phase 2 trial. Phase 3 trials with optimized dosing may show different completion rates. Retatrutide is not FDA-approved.

    Dropout Rates by Dose Group

    Discontinuation Due to Adverse Events

    Dose GroupDiscontinued (%)Completed (%)Avg Weight Loss
    Placebo~3%~97%-2.1%
    1 mg~6%~94%-8.7%
    4 mg~8%~92%-17.1%
    8 mg~10%~90%-22.8%
    12 mg~10-16%~84-90%-24.2%

    Approximate rates. The 12 mg range reflects different escalation schedules within the dose group.

    Why People Quit

    The primary reasons for discontinuation mirror the side effect profile:

    • Nausea (most common): Persistent nausea during dose escalation was the leading cause of dropout. While most nausea is mild-moderate and transient, some participants found it intolerable.
    • Vomiting: More severe than nausea, vomiting was the second most common reason.
    • Diarrhea: Persistent diarrhea led some participants to discontinue.
    • Multiple GI symptoms: Participants experiencing several GI symptoms simultaneously were more likely to quit than those with a single symptom.
    • Non-AE reasons: A small number discontinued for reasons unrelated to side effects (personal choice, moved, lost to follow-up).

    When People Quit

    Dropout timing is informative:

    • Most dropouts occurred during dose escalation: The period when doses increase is when GI side effects peak. Once patients reach their target dose and stabilize, dropout rates decrease significantly.
    • First 8-12 weeks: The highest risk period. Patients who make it past the initial escalation phase are much more likely to complete treatment.
    • Steady state: Once at a stable dose for several weeks, side effects typically diminish and tolerability improves.

    How This Compares to Other Drugs

    DrugDiscontinuation RateAvg Weight Loss
    Semaglutide 2.4 mg~7%-14.9%
    Tirzepatide 15 mg~7%-22.5%
    Retatrutide 12 mg~10-16%-24.2%

    The pattern is clear: more potent drugs with more receptor targets tend to have slightly higher discontinuation rates. But the magnitude of additional weight loss (24% vs 15-22%) far outweighs the modest increase in dropout risk. And for the 84-90% who complete treatment, the results are unparalleled.

    Expected Phase 3 Improvements

    Phase 3 trials incorporate lessons from Phase 2 to improve tolerability:

    • Slower dose escalation: More gradual increases allow the body more time to adjust
    • Optimized escalation intervals: Longer periods at each dose step before increasing
    • Refined dose selection: The most effective dose with acceptable tolerability may differ from Phase 2
    • Better patient education: Setting expectations about transient GI side effects helps patients persist through the adjustment period

    Well-Tolerated Options Available Now

    Current GLP-1 medications have excellent completion rates and are available through TRIMI:

    Learn more about how to get started.

    Medical Disclaimer

    Retatrutide is investigational and not FDA-approved. Dropout data from Phase 2 (Jastreboff et al., NEJM 2023). Phase 3 dropout rates may differ. If you experience intolerable side effects on any medication, consult your healthcare provider before discontinuing.

    Well-Tolerated Treatment Available Now

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    Sources & References

    1. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. NEJM 2021;384:989-1002.
    2. Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity. NEJM 2022;387:205-216.
    3. Lincoff AM et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. NEJM 2023;389:2221-2232.
    4. FDA Prescribing Information for Wegovy (semaglutide) and Zepbound (tirzepatide).
    TCCT

    Written by Trimi Clinical Content Team

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